[Windows Mobile Development and Hacking General] d0ugie:
So I read this fuzemobility.com article about battery life and thought I'd write a super long comment with sweet hyperlinks but it turned out to be too long for their blog configuration. So my XDA friends, here it is. I invite you to contribute any tips and insight you may have to the handful of gems I came up with about gems other people came up with:

WMLongLife by Chainfire, the venerable codemaster known most for wmwifirouter (even though his other work is awesomely impressive), drops you down from H*/3G to EDGE when your screen shuts off for a minute. It will also kill the data connection if inactive for a minute. When you turn the screen back on, it stays on edge, but if you start an app from a 3G whitelist you make, like including Opera and SiriusWM5 but not FlexMail, that app will kick it back into 3G. Switching from edge to 3G takes roughly six seconds he says but probably worth it if you like to save yourself battery (and your gonads from radiation).

Thread

Lumos by nik3r is a great replacement to HTC's included backlight adjusting system. It uses the light meter and you can specify how dim you're willing to go in dark conditions and how bright you have to have it in sunlight. You can tweak every point in between if you want, define what conditions you believe to be bright (and warranting full backlight juice) and dark (running low power). Very low cpu usage, low memory, no battery drain when not using the phone, no cpu involved with fluttering backlight levels, delightful gui frontend, fun to configure. Requires phone with a light meter like the Raphael and Diamond.

Thread

IMAP-Idle or push activesync or instant messaging or PocketPuTTy or PocketIRC or PornTube or anything that keeps the data connection open, even with very little throughput going on, drains substantially harder than having no data connection (just phone, SMS) so use that knowing you're sacrificing battery life (which I do). I'm not sure about this but if you like to use AIM and have an unlimited text messanging plan, using an sms-based IM client like OZ Messenger/Mobile IM may use less juice than something like Agile or IM+ which keeps the connection alive. What I am right about is insisting that you use Outlook Email Scheduler to specify Pocket Outlook synchronizing frequencies over peak and off-peak hours, brilliant program (also does imap idle!!). So with this, in addition to "push" mail which now supports gmail (it's actually called IMAP-idle with non-Exchange mail servers), you can set your phone to cycle pocket outlook synching, say, every five minutes during the day and every half hour after 10pm, whatever you want.

Thread, website.

This one is more for convenience than it is a miracle battery saver, but Touch InCall Screen Tweak by StevePritchard shuts your screen off when you take a call and put the thing to your head and, using the light and g-sensor, when you pull it away as if to dial in your calling card it lights it back up and when you put it back to your head, it dims it. Very handy. The NoSleepRaphael killer.

Thread.

I definitely do not recommend trying this if you are afraid of danger or bricking your phone but here are two links for you crazy underclockers. I can't tell so far if it does in fact successfully throttle my processor, I can't tell if I was able to get the speed back up either by setting it back or by uninstalling, I just don't know but here it is. Couldn't find much feedback so if any of you know how to test battery drain and also don't care about warranty compliance, maybe post results in this thread which I have no doubt will blow up into huge popularity ;). You must have a Qualcomm MSM7XXX(A)-based processor, so google first to double check:

nueDynamicClock, nueClockControl

Raphael/Touch Pro/Fuze users: Make sure you got the right radio with the right rilphone.dll properly installed. If you're AT&T grab 1.12.25.19, not 1.14.25.05 (I've only seen mixed reviews and I myself was not breathtaken it), and then Chainfire and P1Tater's 1.12.25.19/rilphone.dll combo cab. If you're not AT&T, I believe you want to stick to 1.11.25.01 (and grab the right rilphone cab accordingly). If you're fully Olipro-unlocked, you probably know enough about non-Raphael radios and don't need my advice.

Raph radios, Chainfire/P1Tater raph rilphones.

Rhodium Manila is badass, I know, and I have a lot of respect and appreciation for xboxmod and his posse (I'm really in awe) but don't use Rhodium Manila if you want to save battery life (or ram or storage or cpu) more than you want to be dazzled by TP2TF3D. Use pjc's ripped oldschool HTC Home (vga) with TodayAgenda underneath. Maybe SPB Mobile Shell's better than regular Manila, it's probably better than Rhodium Manila (in terms of battery at least) unless you're spinning the 3D stuff nonstop. I don't know about WM6.5's efficiency. Just flashed it. If you know, post. SPB Mobile Shell's trialware btw.

PJC's HTC Home thread, TodayAgenda's site, SPB's site.

If you try to do your own power tests to contribute your scientific studies to your local Ultimate Radio Thread, keep in mind that in lower signal areas your phone must crank out bigger radio waves to reach the tower. So you must be careful to keep everything constant except the variable, the radio, including the time-range during the day you do battery and bandwidth tests (including weekdays versus weekends when switching from one to the other) as in dense areas, capacity gets maxed out with carriers who don't have enough infrastructure to handle the loads. I get this all the time even in Manhattan where you'd think AT&T would get their poop together.

You could cruise through the Accessories forum of your phone (here's the Raphael's) to hunt down an extended life battery but those tend not to be cheap, they make your phone thicker, you have to recalibrate your phone's mechanism to measure battery power and the initial charging training is a ***** and there's a chance you'll get ripped off so consider just buying an extra OEM battery and maybe an extra charger for your office. They fit well in that little secret pocket of your jeans, unless you already use it for a zippo lighter.

Contrary to popular belief, there is no memory effect issue with lithium ion batteries. Don't do full discharges with this intent. Don't do that. Your battery's longevity diminishes over usage, including deliberate discharges. Best bet, for a phone you rely on, is to charge whenever you can charge. Yes a battery's longevity diminishes faster over time if you store it with a full charge (verus 50%) extendedly, but hey, you need that sucker ready to go so use it and buy another one eventually. Temperature and resistance also accelerates decline meaning if you use an equivilant amount of milliamp hours over a week with your phone on standby versus four hours using GPS or wifi, and you do this a lot, it takes a heavier toll on your battery. If you have two batteries and tether or GPS or wifi a lot and then are in situations where you don't do that, consider designating with a sharpie one battery for brutal use and the other for light use. If you're draining heavily over long periods of time while charging your phone, that eats away at your battery's long-term longevity the same as if you used it and then charged it. Actually probably a little more because charging your battery heats it up even hotter than tethering all your pr0n which hurts. Two batteries. Drop $45 at your local dealer or search on froogle to save a few bucks.

According to IRC, there is no idle drain difference between regular 3G and HSDPA (but there is between either of those and EDGE). It all comes down to throughput, not the protocol; however, if you're in a rural area where there is only EDGE, you probably want to shut off 3G as, I'm told, your phone eats up considerable juice by trying to search for a 3G tower. Note that charging on USB theoretically gives you 500mA tops (more like 400 at best) whereas your charger is 1A (at least for the TP). If your phone gets hotter than 43 degrees celsius (use BatteryStatus or this Battery.zip which is a ppc exe to monitor temperature and drain) it will, based on my studies, charge slower, and not at all at 47. ABCPowermeter, by the way, does not work on Touch Pros and I'm guessing on its cousins either.

That's it I'm done. :)

Doug